1. Field of the Invention
The present invention relates to the transmission of electrical signals and compressed air through a rotary joint or connector. The invention more particularly concerns a rotary connector which takes the form of an automotive clockspring.
2. Discussion of the Background
Clocksprings are well known in the automobile industry. An automotive clockspring is an electrical connector or rotary transducer which electrically connects a rotatable airbag assembly mounted on the steering wheel to stationary crash sensors located elsewhere on the vehicle. An automotive clockspring typically includes a housing and a cover mounted to the housing so as to form a cavity therebetween. Rotatably mounted within the cavity is a hub. The clockspring housing is non-rotatably mounted to the steering column, while the hub is attached to the rotatable airbag assembly. A flat ribbon cable is wound around the hub. One end of the flat ribbon cable terminates at the stationary housing or cover and the other end terminates at the hub. The end of the flat ribbon cable terminated at the hub is then connected to an electrical cable which connects to the airbag assembly. During use, the flat ribbon cable is either spooled or un-spooled around the hub when the steering wheel is rotated in one direction or the other direction. Examples of clocksprings are provided in U.S. Pat. Nos. 5,785,541, 5,601,437, 5,580,259, 5,490,793, 5,487,667, 5,460,535, 5,429,517, 5,980,286, and 5,775,920 all of which are hereby incorporated herein by reference.
Devices other than airbags are also mounted on the steering wheel which receive electrical signals. As the automotive industry has matured, vehicles have become more refined as fueled by consumer requirements. Vehicles that appeal to the consumer-mass-market typically have controls and features which are within an arm's length of the driver. To reduce the amount of effort on the part of the driver and to increase the comfort of the driver, more and more functions, switches, and controls are placed ever closer to the driver. Since the driver's hands are on the steering wheel, automobile manufacturers have been placing electrical switches on the steering wheel so that the driver can activate the electrical switches with one finger while keeping their hands on the steering wheel.
Thus, there is a need for increasing the comfort of drivers of automobiles while the drivers keep their hands on the steering wheel.